Synthesis of Co-, Co-Zn and Ni-Zn ferrite powders by the microwave-hydrothermal method

Co-,Ni-Zn, and Co-Zn ferrites were prepared with nanosize well-developed spinel phases by the coprecipitation and microwave-hydrothermal (M-H) methods. X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques showed that the average particle size of ferrites obtained by the M-H process is about 10 nm. In the Co-ferrite system, single-phase ferrites with a spinel structure began to form at a relatively low temperature (100°C) in a short holding time (30 min). The lattice parameter of M1−xZnxFe2O4 systems (M = Ni or Co, 0 ≦ x ≦ 1) increased with an increase of Zn concentration. The crystallization of the spinel ferrites was promoted by the increase in reaction temperature and time.